BAKER CITY, Ore. – Interstate 84 was closed east of Baker City on Saturday morning after a crash involving more than a dozen semi-trucks and hazardous materials, the Oregon Department of Transportation said.

The crash occurred just before 5 a.m. on the eastbound freeway near milepost 318. An estimated 20 vehicles drove onto black ice and crashed, according to Oregon State Police.

Four people were taken to hospitals with unspecified injuries.

Police estimated 50 vehicles were blocked within the crash scene.

“All travelers are advised to take alternate routes to bypass I-84 in eastern Oregon,” ODOT said in a news release.

Two trucks were hauling hazardous materials, police said. Hazardous materials crews were called to the scene.

Westbound I-84 was closed in Ontario at Exit 371. Eastbound I-84 was closed at Exit 304 in Baker City, Exit 265 in La Grande and Exit 216 east of Pendleton, according to ODOT.

The closure was expected to continue throughout the day.

An alternate route for trucks will be Highway 97 south from Biggs Junction, then Highway 20 east from the Bend area, ODOT said.

Eastbound freeway reader boards were activated along I-84 to let drivers know about the crash.